# Today's exoplanet weather: 1,000°C, glass rain, 8,700 km/h winds

Those readers who enjoy complaining about the weather might like to consider a short weekend break on 'hot Jupiter' exoplanet HD 189733b, where conditions will give them something to really moan about. Studies of HD 189733b – discovered in 2005 transiting the star HD 189733, which lies some 63 light years from Earth in the …

1. #### I wonder how much longer it'll be around?

With those sort of temperatures the atmosphere must be boiing off at a fantastic rate even with the relatively strong gravity.

1. #### Re: I wonder how much longer it'll be around?

"the atmosphere must be boiing off at a fantastic rate even with the relatively strong gravity"

And Wikipedia doth spoke unto the internet "this planet is evaporating at a rate of 1-100 gigagrams per second."

Using the upper bound of 100 million kilograms per second, and noting the mass of 1.162 Jovian masses (or 2.2 x 10^27 kg), you'll need 2x10^19 seconds to evaporate it, or 697 billion years. At the lower bound, multiply that by a factor of 100.

But that's a sloppy linear extrapolation. As the mass drops, escape velocity will drop and the mass loss will accelerate on an exponential curve that I'm too lazy to calculate.

On the gripping hand, the K1V primary of 0.846 solar masses has a main sequence life span of 15 billion years, so I doubt the planet will boil away before it has to deal with red giant problems. With a near-circular 0.03AU orbit, HD 189733b will have a front row seat to such stellar change-of-life issues.

1. #### Re: I wonder how much longer it'll be around?

While I applaud your calculations, I'll have to mark you down for use of non-standard units.

The correct measurement of mass on El Reg is the Jub (the mass of the planet being 5.23 x 10^23 KiloJubs). Do keep up.

http://www.theregister.co.uk/Design/page/reg-standards-converter.html

1. #### Re: I wonder how much longer it'll be around?

"The correct measurement of mass on El Reg is the Jub (the mass of the planet being 5.23 x 10^23 KiloJubs). Do keep up."

Someone mentioned "free donuts!" and I prioritized reaching the donut box before the descending horde over niceties like unit conversions. Hence my crude and unpolished post, for which I apologize.

2. #### Re: I wonder how much longer it'll be around?

Kudos for the calculations and all, but I can't really appreciate any of it since my brain is still frozen on the "they measured windspeed on another planet?!?!?!?" part.

Well done, boffins!

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2. #### maybe i'm ignorant but...

how can a gas giant be both tidally locked and have circulating 5000mph winds?

gasses are quite difficult to 'lock' into place.

the researchers also say that they compensated for the planets spin, but if it's locked then its spin is the same period as its orbit and over a transit period won't have rotated much at all...

confused.com

1. #### Re: maybe i'm ignorant but...

Gas giants have a solid centre.

1. #### Re: maybe i'm ignorant but...

I thought gas giant's had secret entry points for a network of wormholes at their centre?

2. #### Re: maybe i'm ignorant but...

Ignoring the possibility of a solid core most of the planet will not be gas but liquid. This can become tidally locked* (especially if its viscous) but this still leaves the atmosphere to move around. As one side is facing its sun it gets very hot and the other side is cold. This is all is a small butterfly to flap its wings and the temperature differences will whip up massive storms and winds - especially when you have glass precipitating out.

Even the small rotation as it rotates round the sun is enough to generate a pretty hefty Coriolis effect.

* there's probably a surface layer of relatively free moving liquid.

3. At 5000 mph the winds would make the planet hot from friction, let alone sticking it next to a sun. God works in mysterious ways indeed.

4. #### Friday on my mind

At least lighting a barby at the weekend won't be a problem there, what with the meat coming ready cooked.

1. #### Re: Friday on my mind

Personally, I struggle to light my barbie if the wind speed is anything greater than, well, about 1mph.

Plus, having a bucket of water to hand just in case may also prove problematic.

2. #### Re: Friday on my mind

That's a hefty freezer you're going to need to keep it from spoiling

3. #### Re: Friday on my mind

what with the meat coming ready cooked.

.. for those who like it crispy..

Oh, hang on, bacon!!

5. This place is the anti-Skegness. Sure, there's a screaming gale off the sea and it's pissing it down. The difference is that the precipitation is warm - thus eliminating the risk of freezing to death. You'll need some pretty good sunblock but your deckchair will still blow over. I bet the nightlife is better than Skeggy too...

1. #### re Skeggy

the rain there is glass - so its not completely anti-Skeggy on a Saturday night.

1. #### Re: Skeggy

The other major difference being that HD 189733b appears to have an atmosphere.

1. #### Re: Re: Skeggy

One thing in common: absence of intelligent life.

1. #### Re: Skeggy

That's rather unfair. We don't know for certain that HD 189733b doesn't have intelligent life.

1. #### Re: Skeggy

One thing is clear; if it does have intelligent life they won't be arguing about the desirability of building wind turbines. A simple nickel alloy rotor a few tens of centimetres in diameter will drive the air conditioning for an average household. But being a wind turbine servicebeing would not be a fun job.

6. #### Supersonic wind

What does that sound like? One continuous sonic boom?

7. #### Hasn't Astronomy Come a Long Way, Fast?

It's not that long ago [well within my adult lifetime and I'm not *that* old] that we were only able to speculate on the probability that there were planets orbiting other starts.

Now, not only have we found and catalogued thousands of the buggers, we're even able to speculate on their composition and calculate the wind-speeds in their atmospheres. Quite mind-blowing, when you think about it.

Hats off to the astro-boffins and trebles all round!

1. #### Re: Hasn't Astronomy Come a Long Way, Fast?

I agree. I was going to post that this was the most amazing science-y thing I've read in some time, being able to measure the wind speeds on a planet 63 ly away, but you beat me to it!

1. #### Re: Hasn't Astronomy Come a Long Way, Fast?

"being able to measure the wind speeds on a planet 63 ly away"

It shows the advantages of a transparent medium, given that we have difficulty measuring what is just a few tens of kilometres away under our feet.

2. #### Quite mind-blowing, when you think about it.

At 5000 mph plus, quite.

Thanks, it's the asbestos one with the wildly flapping tails

8. One ticket please, one way under the name of my boss.

It's Friday afternoon- 13 minutes to beer o' clock, now is not the time for him to come over and want his laptop fixed, again, because of his predilection for "specialist" websites has made it go funny while doing his weekly report.

As title

10. #### So let me get this straight

They have determined the wind speed on a planet 63 light years away by measuring the Doppler shift in a gas in the atmosphere of said planet as it crosses the glaring face of its parent star?

Wow. Just F'ng wow.

I know others have already commented on it but it hears repeating.

Wow, Just F'ng wow.

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